Although the wood is a useful material widely used in various fields, it has a disadvantage of being decayed by wood-destroying fungi and degrading, which causes significant deterioration in the strength. Hence, various inorganic and organic preservative agents have been conventionally used in order to prevent deterioration by various wood-destroying fungi. However, it has been pointed out that such agents have a problem of imposing a huge impact on the human body and a great burden on the environment when they are used in high concentration. Hence, there is a great demand for a more effective preservative agent, which is economical and has a small environmental load.
3′-isopropyl-5-methyl-2-trifluoromethylfuran-3-carboxylic acid anilide (may be hereinafter referred to as “compound A” for short) and 3′-isopropoxy-5-methyl-2-trifluoromethylfuran-3-carboxylic acid anilide (may be hereinafter referred to as “compound B” for short) used as an active ingredient in the present invention belongs to the carboxamide fungicide. There are a number of documents relating to the carboxamide fungicide since old times. For example JP-A-S53-9739 (Patent Document 1) (U.S. Pat. No. 4,093,743) proposes o-trifluoromethyl-m′-isopropoxy benzoic acid anilide to control rice sheath blight, JP-B-S53-12973 (Patent Document 2) (U.S. Pat. No. 4,123,554) proposes 2-methyl benzanilide derivative as a bactericide for agricultural and horticultural use, JP-B-S55-41202 (Patent Document 3) proposes benzamide derivative having a specific structure as an agricultural and horticultural fungicide, JP-A-S60-197603 (Patent Document 4) proposes o-trifluoromethyl-m′-isopropoxy benzoic acid anilide as a Serpula lacrymans control agent, JP-B-S63-38966 (Patent Document 5) proposes a compound of 2-substituted benzanilide compound having a specific structure as a wood preservative and antifungal agent, JP-A-H01-143804 (Patent Document 6) (U.S. Pat. No. 4,942,178) discloses 3′-isopropyl benzanilide derivative having a specific structure as a fungicide for agricultural and horticultural use, JP-B-S48-1171 (Patent Document 7) proposes an acid anilide derivative having a specific structure as a composition for a fungicide, JP-B-S50-10376 (Patent Document 8) (U.S. Pat. No. 3,959,481) proposes a furan-3-carboxyamide derivative having a specific structure as a composition to protect plants from diseases, Japanese Patent 2825745 (Patent Document 9) (U.S. Pat. No. 5,977,168) proposes a dimethylfurancarboxyanilide derivative having a specific structure as a wood preservative and Japanese Patent No. 2951772 (Patent Document 10) and Japanese Patent No. 3083659 (Patent Document 11) disclose 2,5-dimethylfuran-3-carboxyanilide as a wood preservative composition or a wood preservative. However, these publications neither disclose compound A or B of the present invention nor mention a synthesis example, activity to wood-destroying fungi or the like of the compounds.